Generally, a semiconductor memory device has a temperature sensor to control the operational condition of internal circuits according to internal temperature. A conventional temperature sensor generates digital code temperature data including internal temperature data, reads the temperature data to combine codes and generates a temperature signal. The temperature signal generated from the temperature sensor is utilized to control the operational condition of internal circuits in the semiconductor memory device. The temperature signals generated from the temperature sensor include a temperature signal corresponding to an internal temperature of a semiconductor memory chip generated to change a self refresh cycle and a temperature signal which is enabled when an internal temperature of the semiconductor memory chip is high.
FIG. 1 is a diagram illustrating a configuration of a conventional temperature data output circuit.
As shown in FIG. 1, the conventional temperature data output circuit includes a temperature sensor 1 which generates a temperature signal TQ enabled when an internal temperature of a semiconductor memory chip, specifically, a junction temperature of a semiconductor memory chip exceeds a predetermined level, and an output driver 2 which drives the temperature signal TQ and outputs it to a TQ pad 3.
The temperature data output circuit as configured above outputs the temperature signal TQ of high level to the TQ pad 3 when the internal temperature of the semiconductor memory chip exceeds a predetermined level.
In the case that a multi chip package MCP is configured by mounting more than two semiconductor memory chips on the MCP, the internal temperatures of the mounted semiconductor memory chips are variable according to the mounting position or design method. However, since the mounted semiconductor memory chips output internal temperature data of corresponding semiconductor memory chip through respective TQ pads, it is impossible to extract and output only the temperature signal output from the semiconductor memory chip having the highest internal temperature among mounted semiconductor memory chips.